Optical coherence tomography of the performance of the first and second generation of the drug-eluting bioresorbable vascular scaffolds. Source: European Heart Journal

SAN FRANCISCO--In a first-in-man clinical trial, a drug-eluting stent (DES) with a bioabsorbable polymer was shown to be non-inferior to a standard DES with a durable polymer in patients with coronary lesions. Ian Meredith, director of MonashHeart and Executive Director of Monash Cardiovascular Research Centre in Melbourne, Australia, presented the results Nov. 11 at a late breaking clinical trial press conference at the 23rd annual Transcatheter Cardiovascular Therapeutics (TCT).

Meredith and colleagues designed EVOLVE, a prospective multicenter study, to assess whether two dose formulations, one full dose and the other half dose, of the Synergy stent (Boston Scientific) were non-inferior to the Promus Element stent.

“What we tested in this trial was whether you can go from delivering the same dose of drug on conformable, durable polymer of a certain load, reduce that polymer load to a tiny fraction with the same kinetic group profile and same load, and achieve the same results. And the answer is you can.”

They enrolled 291 patients with de novo native coronary lesions (more than 50 percent stenosis) between July 29, 2010, and January 20, 2011, at 29 sites in Europe, Australia, and New Zealand and randomized them into three groups: full dose Synergy (94 patients), half dose Synergy (99) and Promus (98). Exclusion criteria included a recent MI, acute MI, left main disease or chronic total occlusion.

The primary clinical endpoint was the 30-day rate of target lesion failure, defined as cardiac death related to the target vessel, MI related to the target vessel, or target lesion revascularization. The primary angiographic endpoint was six-month in-stent late loss. Late loss is an angiographic variable that measures the difference between the gain achieved by stenting and the fraction lost when tissue grows back over time, he explained.

The full-dose stent group had a late loss at six months of 0.10 mm and 30-day target lesion failure was 1.1 percent, Meredith said; the half-dose group had late loss at six months of 0.13 mm and 30-day target lesion failure was 3.1 percent; and the Promus group had a late loss at six months of 0.15 mm and no target lesion failures at 30 days.

“The results really support the safety and efficacy of this novel bioabsorbable polymer Synergy everolimus-eluting stent for the treatment of patients with de novo coronary artery disease,” Meredith concluded, adding that more studies that examine clinical event rates and the potential to reduce antiplatelet therapy need to be conducted.

Meredith also pointed out limitations. “The caveats are these are relatively straightforward lesions --no complex patients--and it is six months follow-up, not five years follow-up, but it certainly proves the concept,” he said.

In a later session, panelist John McB. Hodgson, MD, chair of the department of cardiology at Geisinger Health System in Danville, Pa., circled back to the purpose for the EVOLVE trial and other novel and next-generation stents. The overarching goal, he said, is “to reduce inflammation, the specter of late-stent thrombosis and the need for antiplatelet therapies.”